advanced care of your monster

[shaunjohnson]

we've seen less and less go pop lately

but i wanna make sure i take care of mine properly when i get it (looking to make my big comeback to electric in the next few weeks)...

what i can see...
use punch control at least a bit to reduce sudden amp draw
dont lock the brakes up so hard, dial them out a bit so the wheels slow down a lot before they lock

USE HIGH C BATTS!!! so were looking at a continuous draw of 120A preferably w/ the 200a burst if u can get it right?
that should fix the ripple current AND the overvolting of the board under re-gen braking right?
after all...high performance system deserves good batts...why is the option for NIMH even in there??

if i do all of these things and check that i always have latest firmware i reckon i should be alright correct?

so far..everyone ive seen with poped MMM's at the club didnt follow these rules.

shaun

[jnev]

Sounds to me like you'll be running your MMM a lot more than your buddies at the track. All your info was right on.

Another one is to reduce timing advance; it is not 0 by default.

Few don't know what it is and just leave it as is, and some people forget about it. Like me one time after all settings went back to default during a firmware update and things got hotter than usual.

[shaunjohnson]

yeah that one too...i usualy set it to low

[traxxasrevony]

i eliminated the brake amp spikes all together, im runing mech brakes. i just like the smoothness of the mech brakes. and it keeps things cooler which is a plus.

[shaunjohnson]

how are mech brakes smoother?
i love the MMM's brakes
and amp spikes are still there as the ESC still has to stop the motor, castle said somewhere that that can produce up to 20-30 volts across the board...remmeber that there's 40v max volt spike on the regen brakes.

shaun

[Sparky]

The mechanical brakes are a joke. I ran them for about 3 months. The extra weight is not worth it. Plus the brakes fade and always need adjusting. The electric braking is better. Just make sure you don't use too heavy of batteries. I recommend around 500g.

[BrianG]

I think the voltage will be limited to 28v because that is what the TVS device is rated for - assuming it is still functional...

[Aceldama]

In terms of reliability mechanical brakes sure sounds like the wise choice. The ESC and batteries have to deal with those spikes each time you lay on the brakes... the two most expensive and fragile components in the vehicle.

[RC-Monster Mike]

Originally Posted by Aceldama

In terms of reliability mechanical brakes sure sounds like the wise choice. The ESC and batteries have to deal with those spikes each time you lay on the brakes... the two most expensive and fragile components in the vehicle.

I don't completely agree with this statement, though it has its merits. If you are using a 6s controller on 6s with marginal batteries and have "super hard" brake settings, then this statement can certainly ring true. As a matter of practice, I use a 6s rated esc on 5s max to allow some head room. I also use good batteries and only use enough brakes to slow the car - no instant lockup. I have no reliablity issues.
Any time you push a system to its limits, the margin for error gets smaller, so if you want to push the system this way, then mechanical brakes will widen the error margin. If your setup is comfortably within the limits, reliability is not typically an issue. :)

[Aceldama]

Originally Posted by RC-Monster Mike

I don't completely agree with this statement, though it has its merits. If you are using a 6s controller on 6s with marginal batteries and have "super hard" brake settings, then this statement can certainly ring true. As a matter of practice, I use a 6s rated esc on 5s max to allow some head room. I also use good batteries and only use enough brakes to slow the car - no instant lockup. I have no reliablity issues.
Any time you push a system to its limits, the margin for error gets smaller, so if you want to push the system this way, then mechanical brakes will widen the error margin. If your setup is comfortably within the limits, reliability is not typically an issue. :)

Well I can't argue with real experience since I don't even have a 1/8 controller/motor yet (but I'll argue anyway because I'm an idiot). After reading the debate about battery packs between CC and their customers (Zippy packs) I got the impression that under hard braking there is an increased chance of cooking the esc or puffing the pack.

While I can definitely appreciate the simplicity of running motor brakes both mechanically and aesthetically I feel that mechanical brakes do have benefits:

1) Front and rear bias tuning.
2) Offloads the braking strain from the esc, motor and batteries.
3) Brakes are cheap.

One downside that bothers me especially since I plan on running 6s is that having the extra servo is going to put more strain on the MMM BEC.

[RC-Monster Mike]

Most of the failures were counter to what my "best practices" suggest - the units tended to fail when using Zippy packs(marginal) on 6s(beyond my 5s suggestion) and likely with the stock brake settings(beginners tend to plug and play, and the stock brake settings are waaaay too strong).

1)Front/rear bias is indeed a potential advantage, but a properly set up vehicle can minimize or negate this perceived benefit - particularly in light of the extra weight and complexity involved with mechanical brakes that offsets the potential advantage
2)ESC braking can add power back to the battery - as long as you aren't pushing the system to the ragged edge, the "strain" isn't so strenuous
3)ESC brakes are free and don't wear out.

In the end, it is a personal choice. Many folks think they NEED the mechanical brakes, and they very well may need them in the absence of a properly set up vehicle. There really is no right or wrong - just pros and cons of each strategy. :)

[MustGoFaster]

+1 for using the motor as a means of braking.
It's all I use in my 10th scale 4wd AE B44 and that car is on rails!

I echo Mike when he says that car setup is the right tool for making adjustments to handling issues.